Even though he was planning on painting the lettering red, I went ahead and split the letters out from the base of the 3D model and printed them separately with red PLA just to see what it would look like. Once I had assembled it I could see that the radii on the lower left corner of the "T", the right two corners of the"B" and all 4 corners of the "O" were too sharp, so I increased their radii from 2mm to 4mm. It looks a lot more true to the original now.